Nonfragmenting pyrotechnic fire extinguisher

ABSTRACT

The specification discloses a pyrotechnic fire extinguisher comprising an explosive charge and a breakable cover forming a zone near the explosive charge for holding fire extinguishing powder. A heat sensitive metallic fuse extends to the explosive charge and has a portion thereof exposed to the exterior environment to sense for heat. Heat from a fire will ignite the fuse which in turn will cause the explosive charge to explode. This will cause the cover to break open and force the powder outward. In one embodiment the explosive charge is held in a container which is grooved or notched selectively between its ends to prevent fragmentation of the container. Explosion of the charge causes the container to break open to direct the force of the explosion into the powder. In one embodiment the cover also is grooved selectively to facilitate breaking thereof and to prevent fragmentation when the charge is exploded.

United States Patent 1 Williams [451 Sept. 3, 1974 [75] Inventor: Robert A. Williams, Fort Worth,

Tex.

[73] Assignee: Pyro Control, Inc., Fort Worth, Tarrant, Tex.

[22] Filed: Feb. 15, 1972 [21] Appl. No.: 226,792

[52] US. Cl. 169/28, 169/36 [51] Int. Cl. A62c 35/00 [58] Field ot Search 169/26, 28, 2 R, 36

[56] References Cited UNITED STATES PATENTS 870,479 11/1907 Stanley 169/28 X 1,482,522 2/1924 Morriss 169/28 2,373,819 4/1945 Eaton 169/28 2,515,832 7/1950 Moumaud 169/28 UX 2,873,806 2/1959 Bittner 169/28 X 3,482,637 12/1969 Mitchell et a1 169/28 X Primary ExaminerM. Henson Wood, Jr.

Assistant ExaminerMichael Y. Mar

Attorney, Agent, or Firm-Wofford, Felsman,-Fails & Zobal 57 ABSTRACT The specification discloses a pyrotechnic fire extinguisher comprising an explosive charge and a breakable cover forming a zone near the explosive charge for holding fire extinguishing powder. A heat sensitive metallic fuse extends to the explosive charge and has a portion thereof exposed to the exterior environment to sense for heat. Heat from a fire will ignite the fuse which in turn will cause the explosive charge to explode. This will cause the cover to break open and force the powder outward.

ln one embodiment the explosive charge is held in a container which is grooved or notched selectively between its ends to prevent fragmentation of the container. Explosion of the charge causes the container to break open to direct the force of the explosion into the powder. In one embodiment the cover also is grooved selectively to facilitate breaking thereof and to prevent fragmentation when the charge is exploded.

9 Claims, 20 Drawing Figures mm 3w" smranrs NONFRAGMENTING PYROTECI-INIC FIRE EXTINGUISHER BACKGROUND OF THE INVENTION This invention relates to a non-fragmenting pyrotechnic powder dispenser and fire extinguisher employing explosives and a fire extinguishing powder which may be actuated automatically upon the occurrence of a fire or which may be actuated by remote control means.

SUMMARY OF THE INVENTION The fire extinguisher of the present invention comprises an explosive charge, a cover forming a Zone near the explosive charge and a fire extinguishing powder located in the zone. In addition, a heat sensitive fuse ex tends to the explosive charge. Ignition of the fuse causes the charge to explode to break open the cover and to force the powder outward to the exterior environment.

In one embodiment the charge is of a solid form while in another embodiment the charge is held in a container which has weakened portions selectively formed between its ends to prevent fragmentation of the container. Explosion of the charge causes the container to break open in a manner to direct the force into the powder. The cover may be formed of structure which is selectively weakened to facilitate breaking and to prevent fragmentation.

In one aspect, the fuse is metallic in composition and may extend through the extinguisher whereby both ends thereof may be coupled to an electrical system which may be an alarm system or which may be a control system for controlling the actuation of the fire extinguisher.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of one embodiment of the present invention;

FIG. 2 is an exterior view of the embodiment of FIG. I illustrating mounting tabs;

FIG. 3 illustrates the manner in which the inner core or container of the device of FIGS. 1 and 2 is segmented upon explosion of its charge;

FIG. 4 is a cross-sectional view of a core or container similar to that employed in the device of FIGS. 1-3;

FIG. 5 is a cross-section of FIG. 4 taken through the lines 55 thereof;

FIG. 6 is a cross-section of FIG. 4 taken through the lines 66 thereof;

FIGS. 7-I3 illustrate other structural embodiments of the device of the present invention; and

FIG. 14 illustrates the device of the present invention being coupled either to a remotely located alarm or to remote control system that may in turn cut off electrical power selectively or completely.

FIG. 15 is a cross-sectional view of another embodiment employing a solid explosive charge;

FIG. 16 is an end view of the device of FIG. I5;

FIG. 17 illustrates fibre glass braid sheathing employed to facilitate insertion of a primer into the explosive charge of the device of FIG. 15; and

FIGS. 18-20 illustrate other embodiments employing a solid explosive charge in sheet form.

DETAIL DESCRIPTION OF THE PRESENT INVENTION Referring to FIGS. 1-6, the powder dispensing mechanism in one embodiment is illustrated at 21. It comprises an inner container or barrel 23 which in FIG. 1 is formed by a cylindrical tube 25 bonded to two end caps 27 and 29. The assembly forming the container 23 may be formed of a bendible and flexible nonconducting material such as nylon, styrene, polycorbonate, etc. Located in the container23 is an explosive charge 31 such as conventional black explosive powder preferably of the newer smokeless type. Also extending through the container and through the explosive charge is a heat sensitive fuse 33 which may be a bi-metallic composition identified as Pyrofuze and which is a composite of essentially palladium and aluminum. This type of fuse may be ignited by a flame of low order such as that produced by a match. Fuse 33 extends through apertures 27A and 29A formed in the end caps 27 and 29. These apertures, with the fuse inserted therethroughare sealed for example with shellac, glyptol, paraffin or room temperature vulcanizing silicon rubbers. The end caps 27 and 29 also are sealed or cemented to the cylinder 25, for example with phenol, after the container is filled with explosive powder.

Wrapped around the container 23 is a flexible sealed bag 35 for example of polyethylene or aluminum foil and which contains a dry, fire extinguishing powder 37 which is commercially available and for example known as the ABC. type which is suitable for extinguishing all types of fire. It is formed of about 90 percent mono-ammonium phosphate with about 10 percent silicones added to keep it free flowing and to protect it from moisture. The powder instead may be of the BC. type which is useful for extinguishing electrical and flammable liquid fires. This type is about 90-94 percent sodium bicarbonate. The balance of the material is stearates added to keep it free flowing and to protect the sodium bicarbonate from moisture.

The bag of fire extinguishing powder is held in place around the container by a mounting tab 41 and binding tape illustrated at 43 and 45. As shown in FIG. 2, the mounting tab 41 is cross-shaped and comprises two mounting ends 41A and 41B and two perpendicular ends 41C and 41D around which the tape 43 and 45 is wrapped to hold the bag of powder in place around the container. The mounting tab 41 may be formed of light fibre board or plastic. The binding tape 43 and 45 in one embodiment may be mylar adhesive tape. In the arrangement shown in FIG. I, the bag including its outer cover or wall 35A thus holds the powder between the outer cover or wall and the container 23.

As illustrated in FIGS. 4-6, spaced grooves 5 I, 53, 55, 57, 59, 61, 63, and are formed around the outer periphery of the tubular portion of the container 25 between its ends to form weakened portions to facilitate breaking of the container into separate segments between the ends of the container or core. These segments are identified at 71, 73, 75, 77, 79, 81, 83, and 85. Preferably the grooves extend to positions spaced inward from the end caps 27 and 29, for example to the positions shown at 87 and 89 in FIG. 4. As illustrated in FIG. 6, altemate ones of the segments are notched at the center of the container to facilitate the breaking of these alternate segments in half. The notches are illustrated at 91, 93, 95, and 97.

As a fire extinguisher, the device 21 will be located in places desired to protect from fire such as in the attics or eves of buildings, or in or on mechanical devices such as automobiles, airplanes, or military equipment;

As an automatic fire extinguisher, the portions 33A and 33B of the fuse 33 extending out of the container will be exposed to the environment desired to be protected. The heat from a fire will cause the fuse 33 to ignite which in turn will cause the explosive charge 31 to explode. This in turn will cause the container 23 and the outer cover 35A to break and hence force the fire extinguishing powder outward to the exterior to extinguish the fire.

Due to the manner in which the container between its ends is selectively grooved and notched, the powder will be dispersed efficiently and effectively without fragmentation of the container. In this respect, the structure forming the tubular portion of the container between its ends will be broken at the grooves 51, 53, 55, 57, 59, 61, 63, and 65. The unnotched segments 73, 77, 81, and 85 will hold the ends of the container together and hence prevent the container from breaking into a number of separate pieces. The notched seg ments 71, 75, 79, and 83, however will break in half at their notched center positions 91, 93, 95, and 97 and the free ends 71A, 71B, 75A, 75B, 79A, 79B, 83A, and 838, at the center will be forced outward by the explosion to allow the force of the explosion to be evenly distributed into the surrounding fire extinguishing powder to cause the cover 35A to be broken evenly around the periphery thereof to disperse the powder uniformly in all directions. The free ends of the notched segments after they are broken in the middle and forced outward will facilitate breaking and cutting of the outer cover 35A and the binding tape 43 and 45. The notched segments when broken however will not be fragmented or completely separated from the container since their other ends near the end caps still will be attached to the container structure.

In one embodiment, the device 21 may be 3 /2 inches long and the external diameter of the cover 35A may be 2V2 inches. The tubular portion of container 23 may have an internal diameter of three-sixteenths of an inch. Its volume thus will be filled with an explosive powder while the volume between the external diameter of the container and the cover A will be filled with the fire extinguishing powder. Actuation of the de vice when employed for example as a fire extinguisher is very effective due to the chemical flame inhibiting action of the powder and the explosive force which drives the powder into cracks. holes. and burning material. Weatherproof units may be provided for mounting outside of buildings. Smaller units may be safely employed on the interior of buildings because of the nonfragmenting design. For example smaller units may be actuated in hand without physical harm to the person other than an unpleasant deluge of powder.

Instead of the alternate segments 71, 75, 79, and 83 being notched at their centers they could be notched alternately at opposite ends. For example segment 71 could be notched near end cap 27, segment 75 notched near end cap 29, etc.

Although not shown, it is to be understood that the tubular member 25 may be round on the inside rather than having the shape shown in FIGS. 5 and 6.

In the embodiment of FIG. 7, mounting tabs 101 and 103 are coupled to the end caps 27 and 29. Apertures are formed through the end caps and through the mounting tabs to allow the fuse to extend into and out of the container. A breakaway cover 105 is supported on and sealed to the shoulders of the end caps 27 and 29. The breakaway cover in this embodiment may be of foil, thin plastic material, or waterproof paper. The fire extinguishing powder will be located between this cover and the inner container 23. This container may be grooved and notched in a manner similar to that described with reference to FIGS. 1-6.

In the embodiment of FIG. 8, the fire extinguishing device is formed by two cup shaped members 111 and 113 having a grooved and notched charge holding container 115 threaded into apertures 117 and 119 formed through the ends of the members 111 and 113 respectively. Container 115 may be grooved and notched in a manner similar to that described with respect to container 23. Caps 121 and 123 are threaded into the ends of container 115 and the container is filled with an explosive charge 31 and in addition has a fuse 33 extending therethrough and through apertures formed through caps 121 and 123. Seals 125 and 127 are provided to form a suitable seal between members 111 and 113 and the ends of the container 115. The other ends of the cup shaped members 111 and 113 are fitted and cemented into a continuous H section 129 of suitable plastic to form a sealed cover around the inner container 115 and which contains and holds the fire extinguishing powder. A split hoop 131 of plastic surrounds the H section 129 and a stainless steel hose clamp 133 is clamped around the hoop 131. A suitable mount (not shown) is secured to the clamp 133. A threaded port 135 which may be opened and closed by a threaded cap 137 is provided to allow the zone formed between the cover and the inner container to be filled with the fire extinguishing powder 37.

In the embodiment of FIG. 8, the cover formed by members 111 and 113 is formed of plastic, such nylon, and is relatively thick compared with the thin plastic or foil bag 35 of FIG. 1. The exterior cover formed by the members 111 and 113 will be selectively grooved to form holding or non-erupting segments and erupting segments. One end of the erupting segments will break loose and peel back when the charge is exploded.

Segment 141 is a holding or non-erupting segment while segments 143, 145, 147 and 149 are erupting segments. As illustrated in FIGS. 8-10, segment 14] has a continuous thickness from one end of the cover to the other. Segment'143, however, is grooved in a manner whereby its wall thickness becomes thinner from the center or from clamp 133 towards the left end of the cover. Segment 145, however, is thicker at the left end but becomes thinner towards the center or towards the clamp 133. Segment 147 is similar to segment 143 while segment 149 is similar to segment 145. A similar arrangement is provided on the right side of the clamp 133. Continuing around the periphery of the cover there will be another non-erupting segment 141 and another set of erupting segments 143, 145, 147, 149, etc.

When the charge is exploded, non-erupting segments 141 will hold the cover together. Segments 143 and 147, however, will separate at the ends of the cover and peel back towards the center thereof. Segments 145 and 149 will separate at the center of the cover and peel back towards the ends thereof. Thus, the powder will be forced outward in a uniform manner, however, neither the container nor the cover will fragment.

. In the embodiment of FIG. 8, the fuse 33 is braided from a plurality of single strands. The strands at each end are electrically coupled to metallic lugs 151 and 153 held in place by the end caps 121 and 123. Coupling is by way of metallic strands 155 and 157 tied to the lugs 151 and 153 respectively. Strands 155 and 157 may form an integral part of the fuse or may be separate members tied to the lugs 151 and 153 and to the fuse. Electrical conductors may be connected to lugs 151 and 153 to allow current to be passed through the fuse to allow remote monitoring or control to be employed as will be described subsequently. In the embodiment of FIG. 8, the container 115; the cover formed by members 111 and 113; and the caps 121 and 123 and 137 are formed of non-conducting plastic.

Referring to FIGS. 11 and 12, the fire extinguishing device is modified in form that member 161 forms an end cap and mounting plate while member 163 forms an end cap and exterior cover surrounding a grooved and notched container 165. Container 165 may be grooved and notched in a manner similar to that described with respect to container 23. The cover 163 may be formed of aluminum or plastic. It has its end portion 167 cemented and sealed to an annular shoulder 169 extending from the plate 161. In addition it is scored or grooved radially outward from a circle, concentric with the axis of the container 165, to its outer edge 167. Thus when the container 165 is broken or ruptured by the explosive, the cover 163 will separate at the grooved or weakened portions as illustrated in FIG. 12 to allow the powder to be dispersed evenly outward from the device. Due to the manner in which the container 165 and cover 163 are selectively grooved and notched there will be no fragmentation of the device when actuated.

Referring to FIG. 13, there is illustrated a portion of a segmented barrel or container in which a primer 171 such as lead styphnate is brushed or deposited on the inside of the end cap 27 to facilitate actuation of the explosive charge located in the container 23. As illustrated in this embodiment, the fuse 33 does not extend completely through the container and in the embodiments disclosed and discussed previously the fuse need not extend through the container unless it is desired to connect the fuse to an electrical system for example as illustrated in FIG. 14.

In the system of FIG. 14 the fuse 33 does extend through through the container 23 and through the explosive charge located therein and opposite ends 33A and 33B are coupled to non-heat sensitive electrical conductors 173 and 175. As described with respect to FIG. 8, the fuse 33 may have opposite ends tied to lugs 151 and 153 and conductors 173 and 175 may be tied to lugs 151 and 153, respectively. Conductors 173 and 175 in turn extend to a small source 181 of electrical energy which in turn is coupled to an alarm system 183 by way of a closed switch 185. The source 18] applies a small value of electrical current through the fuse 33 and through the alarm system 183. The value of the electrical current is small enough to prevent ignition of the fuse 33. In normal operation, the alarm system may be of the type which is inactive as long as the current flow from the source 181 passes through the alarm system. Upon the occurrence of a fire and ignition of fuse 33, current flow will be terminated or interrupted and the alarm system will be actuated. The alarm system 183 may be located at a position remote from the fire extinguisher 21. In the system of FIG. 14, two alarms will be given upon the occurrence of a fire, the sound produced by the device 21 upon explosion thereof and in addition the sound or warning system produced by the alarm system 183.

In a further modification, the alarm system 183 may be eliminated and a source 181 of electrical energy provided which may be sufficient to cause controlled ignition of the fuse 33 when the switch 185 is closed.

In operation of this modified system, normally the switch 185 will be open and the fire extinguisher 21 actuated by closing the switch 185. This modified system may be employed for example at remote positions such as aircraft engines, etc. and actuated in a controlled manner by the operator for example upon visually spotting the flames or smoke from a fire in the engine.

Although the system discussed in the preferred embodiment is employed as a fire extinguishing device, it is to be understood that it could be employed for protection purposes to mark and repel molesters. In this respect, the fire extinguishing powder would contain a dye or repellent to mark or repel the molesters when the device was automatically actuated or actuated by controlled means. i

In one embodiment, the bi-mettalic fuse is of the type manufactured by Pyrofuze Corporation, an affiliate of Sigmun Cohn Corporation, 121 South Columbus Avenue, Mt. Vernon, NY. 10553. The fuse may be a single strand for example or a woven braid fabricated from a plurality of single strands. Each strand may be formed of an outer shell of palladium and an inner core of aluminum.

Although in the preferred embodiment, a bimetallic fuse is employed, it is to be understood that other type of fuses could be used, for example heat sensitive fuses of the powder type such as those used in fireworks, etc. With fuses of this type the device will not be coupled to an electrical system.

Referring now to FIGS. 15-20 there are disclosed other embodiments wherein a solid explosive charge is employed thus eliminating the need of the inner container for holding the charge. The devices of these embodiments have advantages in that they are simpler and easier to construct. In addition, the possibility of fragmentation is reduced even more. The solid explosive may be of the flexible type manufactured by Dupont Corporation and known as Deta-Sheet, Deta-Tube, or Deta-Cord. In FIG. 15., the solid explosive charge is shown at 201 and is in tubular form. Extending into each end of the tubular charge 201 are thin plastic tubes 203 and 205. Extending through the charge 201 and through the tubes 203 and 205 is a metallic heat sensitive fuse 33 with a primer 207 surrounding the fuse and located within the charge 201. Although not shown, the outward ends of the tubes 203 and 205 will be sealed. Surrounding the charge 201 and the tubes 203 and 205 is a flexible and breakable bag 209 for holding the fire extinguishing powder 37. The bag 209 is secured in place by binding tape illustrated at 211 and 213. Explosion of the charge 201 will cause the bag 209 to break open to force the powder 37 outward. FIG. 16 is a side view of the fire extinguisher of FIG. 15 but illustrating three [breakable bags 215, 217 and 219 of fire extinguishing powder tied and secured around the charge.

In FIG. 17, a fibreglass braid sheathing 221 is illustrated as being employed to facilitate insertion of the primer into the tubular charge 201.The sheathing may be pushed together in the center as illustrated at 223 and this portion soaked in the primer in liquid form. The sheathing then may be pulled straight to allow the primer to dry in place and the sheathing, with a fuse extending therethrough, may be inserted into the tubular charge 201 to the desired position.

In the embodiment of FIGS. 18 and 19, a solid explosive charge in sheet fortn may be used in the fire extinguisher. The charge illustrated at 231 is bonded or glued to a rectangular mount 233 of strong plastic material. Formed in the top surface of the mount and across its length is a notch 235 in which a fuse 33 is inserted with a suitable primer. Overlaying the charge 231 is a flexible and breakable bag 237 of fire extinguishing powder 37. The bag 237 is secured over the charge 231 and to the mount 233 by a rectangular frame 239 and bolts 241. As illustrated, the frame 239 binds and holds the edges of the bag 237 to the mount 233. The mount 233 is strong enough to resist rupture upon explosion of the charge. The device of FIGS. 18 and 19 is directional in that the fire extinguishing powder will be forced or blown outward to one side of the mount 233 when the charge 231 is exploded and the bug 237 broken open.

The embodiment of FIG. 20 is similar to that of FIGS.

18 and 19 but modified in structure. A breakable plastic cover 251 is employed to hold the fire extinguishing powder over and next to the solid sheet charge 231. The edges of the cover 251 are glued and sealed to the top surface of the mount 233. A notch is formed in the top surface of the mount between two apertures 253 and 255 extending through the mount. The fuse 33 is layed in the notch and has opposite ends extending through the apertures 253 and 255. A suitable primer 257 is provided in contact with the fuse 33 and the sheet charge 231 is glued or bonded over the fuse and primer and to the mount 233. The cover 251 with the fire extinguishing powder then is sealed to the mount over the sheet charge. Explosion of the charge 231 will cause the cover 251 to break open .to force the fire extinguishing powder outward to one side of mount 233. The cover 251 may be selectively weakened to ensure proper rupture without fragmentation when the charge is exploded.

I claim:

1 A pyrotechnic fire extinguisher comprising:

an explosive charge,

a cover forming a zone near said explosive charge, a fire extinguishing powder located in said zone, and

a heat sensitive bi-metallic fuse extending to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and to force said powder outward to the exterior environment said fuse having a portion extending out of said extinguisher and capable of igniting in the presence of heat from a fire.

2. The fire extinguisher of claim 1 wherein said fuse is formed essentially of palladium and aluminum.

3. A pyrotechnic fire extinguisher comprising:

an explosive charge,

a cover forming a zone near said explosive charge, a fire extinguishing powder located in said zone, and

a heat sensitive metallic fuse, capable of igniting in the presence of heat from a fire, extending from the exterior of said fire extinguisher to said explosive 8 charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and to force said powder outward to the exterior environment,

said fuse extends through said fire extinguisher whereby both ends of said fuse may be coupled to an electrical system.

4. A pyrotechnic fire extinguisher comprising:

an explosive charge,

structure forming a container,

said explosive charge being located in said container between spaced ends thereof,

said container being capable of breaking open when said charge is exploded,

a plurality of spaced grooves formed in said structure of said container between said ends thereof to facilitate separation of said structure into different segments along said grooves,

predetermined ones of said segments each being notched at positions between said ends to facilitate separation of said predetermined segments at said notched positions whereby said unnotched segments will hold said structure together and said predetermined segments will be forced outward at one end thereof from their notched positions when said charge is exploded,

a cover surrounding said container,

a fire extinguishing powder located between said cover and said container, and

a heat sensitive metallic fuse extending to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and to force said powder outward to the exterior environment,

said fuse having a portion extending out of said extinguisher and capable of igniting in the presence of heat from a fire.

5. The fire extinguisher of claim 4 wherein the structure forming said cover has weakened portions selectively formed therein to facilitate breaking of said cover in a controlled manner.

6. The fire extinguisher of claim 4 wherein:

a plurality of grooves are formed in the structure of said cover to facilitate separation of said cover into different segments;

said cover comprising segments constructed to hold said cover together and allow certain ones of said segments to be forced outward at one end thereof when said charge is exploded.

7. A pyrotechnic fire extinguisher comprising:

an explosive charge,

a cover forming a zone near said explosive charge,

a fire extinguishing powder located in said zone,

a metallic heat sensitive fuse extending to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to-break open and force said powder outward to the exterior environment,

said fuse having a portion extending out of said extinguisher and capable of igniting in the presence of heat from a fire,

said heat sensitive metallic fuse extending through said fire extinguisher, and

an electrical system coupled to both ends of said heat sensitive metallic fuse.

8. The fire extinguisher of claim 7 wherein said fuse 65 comprises a bi-metallic fuse.

9. The fire extinguisher of claim 8 wherein said fuse 

2. The fire extinguisher of claim 1 wherein said fuse is formed essentially of palladium and aluminum.
 3. A pyrotechnic fire extinguisher comprising: an explosive charge, a cover forming a zone near said explosive charge, a fire extinguishing powder located in said zone, and a heat sensitive metallic fuse, capable of igniting in the presence of heat from a fire, extending from the exterior of said fire extinguisher to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and to force said powder outward to the exterior environment, said fuse extends through said fire extinguisher whereby both ends of said fuse may be coupled to an electrical system.
 4. A pyrotechnic fire extinguisher comprising: an explosive charge, structure forming a container, said explosive charge being located in said container between spaced ends thereof, said container being capable of breaking open when said charge is exploded, a plurality of spaced grooves formed in said structure of said container between said ends thereof to facilitate separation of said structure into different segments along said grooves, predetermined ones of said segments each being notched at positions between said ends to facilitate separation of said predetermined segments at said notched positions whereby said unnotched segments will hold said structure together and said predetermined segments will be forced outward at one end thereof from their notched positions when said charge is exploded, a cover surrounding said container, a fire extinguishing powder located between said cover and said container, and a heat sensitive metallic fuse extending to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and to force said powder outward to the exterior environment, said fuse having a portion extending out of said extinguisher and capable of igniting in the presence of heat from a fire.
 5. The fire extinguisher of claim 4 wherein the structure forming said cover has weakened portions selectively formed therein to facilitate breaking of said cover in a controlled manner.
 6. The fire extinguisher of claim 4 wherein: a plurality of grooves are formed in the structure of said cover to facilitate separation of said cover into different segments; said cover comprising segments constructed to hold said cover together and allow certain ones of said segments to be forced outward at one end thereof when said charge is exploded.
 7. A pyrotechnic fire extinguisher comprising: an explosive charge, a cover forming a zone near said explosive charge, a fire extinguishing powder located in said zone, a metallic heat sensitive fuse extending to said explosive charge for causing said explosive charge to explode when said fuse is ignited to cause said cover to break open and force said powder outward to the exterior environment, said fuse having a portion extending out of said extinguisher and capable of igniting in the presence of heat from a fire, said heat sensitive metallic fuse extending through said fire extinguisher, and an electrical system coupled to both ends of said heat sensitive metallic fuse.
 8. The fire extinguisher of claim 7 wherein said fuse comprises a bi-metallic fuse.
 9. The fire extinguisher of claim 8 wherein said fuse is formed essentially of palladium and aluminum. 